Field of the Invention
The invention relates to a wireless communication device and a method for controlling an antenna array, and particularly relates to a wireless communication device supporting a multi-user multi-input multi-output technique and a method for controlling an antenna array.
Description of Related Art
In a wireless local area network (LAN) under an IEEE 802.11n communication standard, an access point adopts a single-user multi-input multi-output (SU-MIMO) transmission technique, i.e. the access point transmits data to each of the user equipment (UE) one-by-one. Along with quick development of wireless communication technology, the communication standard of the wireless LAN has evolved to IEEE 802.11ac, and can support a multi-user MIMO (MU-MIMO) transmission technique. In the MU-MIMO transmission technique, the access point can use a plurality of antenna elements to simultaneously transmit data to a plurality of UEs in a same user group, and the access point can dynamically adjust the members in the same user group.
Generally, smart antennas are applied to the SU-MIMO transmission technique. The smart antenna can be composed of antenna array with reconfigurable radiation pattern or polarization diversity, and the above antenna array corresponds to an antenna index. Moreover, a conventional method for controlling the antenna array is to set the antenna index of the antenna array through a training operation. However, in the MU-MIMO transmission technique, the antenna array has to transmit data to a plurality of UEs simultaneously, so that the conventional method for controlling the antenna array may result in the fact that the access point has to spend a large amount of time to complete setting the antenna index of the antenna array. Moreover, the access point has to complete setting the antenna index of the antenna array before using the antenna array to transmit data to the UEs.
Therefore, regarding the MU-MIMO transmission technique, the conventional method for controlling the antenna array generally results in the fact that the access point cannot complete transmitting data to the UEs before the user group is changed. In other words, the conventional method for controlling the antenna array generally causes the access point to be incapable of using the antenna array with the antenna index to transmit data under the MU-MIMO mode, so that the access point cannot achieve a good interference mitigation effect and a good communication range.